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Adsorption of direct dyes from aqueous solutions by carbon nanotubes: determination of equilibrium, kinetics and thermodynamics parameters.
J Colloid Interface Sci. 2008 Nov 15; 327(2):308-15.JC

Abstract

This study examined the feasibility of removing direct dyes C.I. Direct Yellow 86 (DY86) and C.I. Direct Red 224 (DR224) from aqueous solutions using carbon nanotubes (CNTs). The effects of dye concentration, CNT dosage, ionic strength and temperature on adsorption of direct dyes by CNTs were also evaluated. Pseudo second-order, intraparticle diffusion and Bangham models were adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. Additionally, this study used the Langmuir, Freundlich, Dubinin and Radushkevich (D-R) and Temkin isotherms to describe equilibrium adsorption. The adsorption percentage of direct dyes increased as CNTs dosage, NaCl addition and temperature increased. Conversely, the adsorption percentage of direct dyes decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. Based on the regressions of intraparticle diffusion and Bangham models, experimental data suggest that the adsorption of direct dyes onto CNTs involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium adsorption of DR86 is best fitted in the Freundlich isotherm and that of DR224 was best fitted in the D-R isotherm. The capacity of CNTs to adsorb DY86 and DR224 was 56.2 and 61.3 mg/g, respectively. For DY86, enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were 13.69 kJ/mol and 139.51 J/mol K, respectively, and those for DR224 were 24.29 kJ/mol and 172.06 J/mol K, respectively. The values of DeltaH(0), DeltaG(0) and E all indicate that the adsorption of direct dyes onto CNTs was a physisorption process.

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Authors+Show Affiliations

Kuo CY
Department of Environmental and Safety Engineering, National Yunlin University of Science and Technology, Taiwan, ROC.
Wu CH
No affiliation info available
Wu JY
No affiliation info available

MeSH

AdsorptionColoring AgentsDiffusionKineticsNanotubes, CarbonSolutionsTemperatureThermodynamicsWaterWater Purification

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18786679

Citation

Kuo, Chao-Yin, et al. "Adsorption of Direct Dyes From Aqueous Solutions By Carbon Nanotubes: Determination of Equilibrium, Kinetics and Thermodynamics Parameters." Journal of Colloid and Interface Science, vol. 327, no. 2, 2008, pp. 308-15.
Kuo CY, Wu CH, Wu JY. Adsorption of direct dyes from aqueous solutions by carbon nanotubes: determination of equilibrium, kinetics and thermodynamics parameters. J Colloid Interface Sci. 2008;327(2):308-15.
Kuo, C. Y., Wu, C. H., & Wu, J. Y. (2008). Adsorption of direct dyes from aqueous solutions by carbon nanotubes: determination of equilibrium, kinetics and thermodynamics parameters. Journal of Colloid and Interface Science, 327(2), 308-15. https://doi.org/10.1016/j.jcis.2008.08.038
Kuo CY, Wu CH, Wu JY. Adsorption of Direct Dyes From Aqueous Solutions By Carbon Nanotubes: Determination of Equilibrium, Kinetics and Thermodynamics Parameters. J Colloid Interface Sci. 2008 Nov 15;327(2):308-15. PubMed PMID: 18786679.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Adsorption of direct dyes from aqueous solutions by carbon nanotubes: determination of equilibrium, kinetics and thermodynamics parameters. AU - Kuo,Chao-Yin, AU - Wu,Chung-Hsin, AU - Wu,Jane-Yii, Y1 - 2008/08/27/ PY - 2008/06/25/received PY - 2008/08/19/revised PY - 2008/08/20/accepted PY - 2008/9/13/pubmed PY - 2009/1/13/medline PY - 2008/9/13/entrez SP - 308 EP - 15 JF - Journal of colloid and interface science JO - J Colloid Interface Sci VL - 327 IS - 2 N2 - This study examined the feasibility of removing direct dyes C.I. Direct Yellow 86 (DY86) and C.I. Direct Red 224 (DR224) from aqueous solutions using carbon nanotubes (CNTs). The effects of dye concentration, CNT dosage, ionic strength and temperature on adsorption of direct dyes by CNTs were also evaluated. Pseudo second-order, intraparticle diffusion and Bangham models were adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. Additionally, this study used the Langmuir, Freundlich, Dubinin and Radushkevich (D-R) and Temkin isotherms to describe equilibrium adsorption. The adsorption percentage of direct dyes increased as CNTs dosage, NaCl addition and temperature increased. Conversely, the adsorption percentage of direct dyes decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. Based on the regressions of intraparticle diffusion and Bangham models, experimental data suggest that the adsorption of direct dyes onto CNTs involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium adsorption of DR86 is best fitted in the Freundlich isotherm and that of DR224 was best fitted in the D-R isotherm. The capacity of CNTs to adsorb DY86 and DR224 was 56.2 and 61.3 mg/g, respectively. For DY86, enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were 13.69 kJ/mol and 139.51 J/mol K, respectively, and those for DR224 were 24.29 kJ/mol and 172.06 J/mol K, respectively. The values of DeltaH(0), DeltaG(0) and E all indicate that the adsorption of direct dyes onto CNTs was a physisorption process. SN - 1095-7103 UR - https://www.unboundmedicine.com/medline/citation/18786679/Adsorption_of_direct_dyes_from_aqueous_solutions_by_carbon_nanotubes:_determination_of_equilibrium_kinetics_and_thermodynamics_parameters_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0021-9797(08)01057-6 DB - PRIME DP - Unbound Medicine ER -